Mastering from tape to digital rig question

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Mastering from tape to digital rig question

Post by hannahjazzz »

I’m trying to hook up a revox A77 1/4 inch and get it into my pro tools via an Avalon 96k interface.

I’m wondering what leads I need with minimal interference? Stupid question I know. The Avalon only takes XLR input I think. Ordered it but it hasn’t come yet so
Need to confirm.

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Re: Mastering from tape to digital rig question

Post by James Perrett »

I'm a little confused - I can't see any audio interfaces in Avalon's product range. Or is there a different Avalon company that Google doesn't know about?

It would help if you could give us the make and model number of all the devices that you are using in your signal path.
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Re: Mastering from tape to digital rig question

Post by Hugh Robjohns »

I'm not aware of any DAW audio interface made by Avalon, so can't offer any advice on its connectivity. Can you share a link to the specific product, please?

And what are the available output connectors on your specific model of Revox A77. I've seen some with RCA-phono (cinch) and/or DIN connectors, and others with XLRs.
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Re: Mastering from tape to digital rig question

Post by ef37a »

Having refreshed the old brain, the A77 has both RCA phono and DIN ('radio') outputs but the DIN is via a 4k7 resistor and attenuated by at least 6dB. The RCA output looks to be low source resistance at ~400 Ohms.

I would therefore suggest a simple RCA to 1/4" TS (guitar) jack cable as it would be a strange interface that did not have jacks?

But yes, give us the full SP!

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Re: Mastering from tape to digital rig question

Post by Hugh Robjohns »

ef37a wrote: Wed Sep 22, 2021 3:36 pmHaving refreshed the old brain, the A77 has both RCA phono and DIN ('radio') outputs but the DIN is via a 4k7 resistor and attenuated by at least 6dB.

The 'radio' connection conformed to the old DIN hi-fi standard which evolved with valve equipment and passed the signal as a current, rather than a voltage.

The equivalent input voltage when connected to modern voltage-fed equipment is entirely dependent on the device's input impedance, at a nominal 1mV/ 1k Ohms.

So 100k Ohms input impedance gives 100mV signal level.
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Re: Mastering from tape to digital rig question

Post by ef37a »

Hugh Robjohns wrote: Wed Sep 22, 2021 4:50 pm
ef37a wrote: Wed Sep 22, 2021 3:36 pmHaving refreshed the old brain, the A77 has both RCA phono and DIN ('radio') outputs but the DIN is via a 4k7 resistor and attenuated by at least 6dB.

The 'radio' connection conformed to the old DIN hi-fi standard which evolved with valve equipment and passed the signal as a current, rather than a voltage.

The equivalent input voltage when connected to modern voltage-fed equipment is entirely dependent on the device's input impedance, at a nominal 1mV/ 1k Ohms.

So 100k Ohms input impedance gives 100mV signal level.

Yes Hugh, a lot of people slagged off the DIN connection standard but they did not understand it and it was entirely appropriate for valve based equipment in 'domestic' circumstances. 'Pros' of course could afford cathode follower stages and transformers!

I was in fact expecting a much higher resistance than 4k7? I guess because of the transistors they, like so many others went 'half way'.

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Re: Mastering from tape to digital rig question

Post by Tim Gillett »

The A77 was Revox's first transistor model (all silicon) and an excellent machine. I've never seen one with XLRs though. Output level is adjustable at the front panel.
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Re: Mastering from tape to digital rig question

Post by James Perrett »

Revox themselves didn't make any with XLR's (as far as I know) but various third parties modified them to add balanced inputs and outputs on XLR's.
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Re: Mastering from tape to digital rig question

Post by Hugh Robjohns »

Tim Gillett wrote: Thu Sep 23, 2021 12:27 am I've never seen one with XLRs though.

The A77 tape machine was intended as a domestic/consumer hi-fi product and came with RCA-phono and DIN connections as standard. But the machine became a popular low-cost alternative to professional studio recorders and many were 'studio-ised' which included retrofitting XLRs -- at least in the UK and Europe.
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Re: Mastering from tape to digital rig question

Post by Tim Gillett »

Hugh Robjohns wrote: Thu Sep 23, 2021 9:44 am
Tim Gillett wrote: Thu Sep 23, 2021 12:27 am I've never seen one with XLRs though.

The A77 tape machine was intended as a domestic/consumer hi-fi product and came with RCA-phono and DIN connections as standard. But the machine became a popular low-cost alternative to professional studio recorders and many were 'studio-ised' which included retrofitting XLRs -- at least in the UK and Europe.

Yes, not surprised as they were more compact and much lighter than the Studer equivalents. I believe their much greater portability and general audio quality made them popular for location live to stereo concert recordings on 10.5" reels. Onboard Dolby B was an option, making for potentially even better quality live recordings.
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Re: Mastering from tape to digital rig question

Post by Trevor Johnson »

Yes, not surprised as they were more compact and much lighter than the Studer equivalents. I believe their much greater portability and general audio quality made them popular for location live to stereo concert recordings on 10.5" reels.

Alfred Brendel used an A77 to listen back to his practice.
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Re: Mastering from tape to digital rig question

Post by hannahjazzz »

Trevor Johnson wrote:
Yes, not surprised as they were more compact and much lighter than the Studer equivalents. I believe their much greater portability and general audio quality made them popular for location live to stereo concert recordings on 10.5" reels.

Alfred Brendel used an A77 to listen back to his practice.

Thanks for your response. Would I be wasting my time using a revox with my 1/4 inch tapes to transfer them to digital? I

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